Attempts to design an adjustable mounting for bicycle saddles dates back to 1887, with over 33 patents to date.
Current art divided into roughly four types:
1. A horizontal pivot having toothed locking surfaces perpendicular to the saddle post and the pivot.
2. The top of the post is formed into an enlarged rearwardly projecting head usually having one or more cylindrical surfaces permiting the rotation of the saddle relative to the post by means of an intermediate member having a cylindrical surfaces conforming to the top said cylindrical surface on the head and having a means to clamp the saddle rails as a part of said intermediate member.
This embodiment is divided into three subtypes by either:
2A, Having one bolt to hold and clamp the assembly. PA1 2B, Having two bolts, one to clamp the assembly, and one to adjust or hold the adjustment as set. The latter is commonly known as a "jack bolt". PA1 2C, Having two bolts that act together to perform the adjustment and clamping functions. Type 2C is generally known as the "Teeter-totter" type. PA1 1. Positive locking of the adjustment. PA1 2. Adequate support of the saddle rails. PA1 3. Reduction of weight in the large head. PA1 4. Elimination of a joint between the head and stem. (or a costly part made as one piece).
Type 3: Embodiments eliminating the enlarged head and having the adjusting mechanism on the head of the post itself. They may have one clamping bolt or be two bolt teeter totter assemblies. They may have inserted end plugs or solid ends, but not offset heads.
Type 1A units are not used on high performance or expensive bicycles at this time to a great extent. One objection is the stepwise adjustment imposed by the toothed adjusting surfaces. Without said teeth, the design does not resist high loadings very well. Bird, U.S. Pat. No. 4,231,611 and Kashima, U.S. Pat. No. 4,453,765 are typical disclosures of this type. Since these designs do not accept the double rail saddle, the subject of this invention, they are not discussed.
Type 2A are common on all types of cycles. However the single locking bolt must be large and set very tight to prevent motion under shock loads, and the single bridge holding the saddle rails, unless very wide, leads to bending of the rails; also the saddle adjustment is difficult to reproduce if the unit is dis-assembled for some reason.
Campagnolo, U.S. Pat. No. 3,992,054, Cunningham, U.S. Pat. Nos. 4,155,590, Patriarca, U.S. Pat. No. 4,502,811 and Kashima, U.S. Pat. No. 4,568,121 are typical of headed, single fixing bolt embodiments. Aside from the weight of the head, some means must be provided to attach the head to the stem, or the head must be manufactured by forging, casting or upsetting; all this adds to the cost, and a joint is never as strong as the parent metal. In some designs, changing the saddle angle also affects the for and aft location, an act that may be undesirable. A single clamping bar as shown by Patriarca can lead to bending of the saddle rails under impact loading.
The "Jacking" bolts in type 2B eliminate the adjusting and slippage problems, although many operate in one direction only, thus not preventing motion the other way. Often the "jacking" and "fixing" bolts oppose and load each other requiring larger sizes at least in one bolt to carry the working load also. A typical embodyment is shown in Shimano's U.S. Pat. No. 4,421,357.
The type 3 unit is best illustrated by Shook's U.S. Pat. No. 3,933,391. A inverted form is disclosed by Routens in his U.S. Pat. No. 4,180,345. The wrenching heads of Shook's bolts are on top of the adjustor and are under the seat of the saddle, hence not easy of access. Routen's bolts carry both fixing and working loads together, hence larger bolts are required, and his head is large and heavy.
Kashima, U.S. Pat. No. 4,568,121, FIGS. 10 and 11 and Cunningham, U.S. Pat. No. 4,155,590, FIGS. 6, 7 and 8 disclose single bolt designs of Type 3. All these embodyments require an additional member attached to the end of the stem by welding or other means, and do not provide any means other than friction to preserve the adjustment, thus they require relatively heavy fixing bolts.
Juy, U.S. Pat. No. 4,440,440 discloses the use of a spherical head on the end of a bent stem. He has the same shortcommings of a all headed styles, plus a limited lateral torque resistance and a very specially shaped hole in the head to accomodate the angular adjustment.